Redis实战 - 3.Hash
hash
Redis的Hash有点像一个对象（object），一个Hash里面可以存多个Key-Value对作为它的field，所以它通常可以用来表示对象。
Hash里面能存放的值也能作为String类型来存储，如果Hash里面值的类型可以解析为数字，那么也可以进行自增自减等操作。
HSET HGET
HSET 设置Hash里面的值：
语法：HSET KEY_NAME FIELD VALUE
127.0.0.1:6379> HSET myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HGET myhash field1
"foo"
HMSET HMGET
HMSET：同时将多个 field-value (字段-值)对设置到哈希表中。
语法： HMSET KEY_NAME FIELD1 VALUE1 ...FIELDN VALUEN
HMGET：返回哈希表中，一个或多个给定字段的值
语法：HMGET KEY_NAME FIELD1...FIELDN
127.0.0.1:6379> HMSET myhash field1 "Hello" field2 "World"
OK
127.0.0.1:6379> HMGET MYHASH field1
1) (nil)
127.0.0.1:6379> HMGET myhash field1
1) "Hello"
127.0.0.1:6379> HMGET myhash field1 field2
1) "Hello"
2) "World"
HGETALL
如果想获得Hash所有的Key-Value对，那就使用HGETALL：
127.0.0.1:6379> hgetall myhash
1) "field1"
2) "Hello"
3) "field2"
4) "World"
127.0.0.1:6379>
HDEL
HDEL key field1 [field2]
删除一个或多个哈希表字段
redis 127.0.0.1:6379> HSET myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HDEL myhash field1
(integer) 1
redis 127.0.0.1:6379> HDEL myhash field2
(integer) 0
HEXISTS
HEXISTS key field
查看哈希表 key 中，指定的字段是否存在。
redis 127.0.0.1:6379> HSET myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HEXISTS myhash field1
(integer) 1
redis 127.0.0.1:6379> HEXISTS myhash field2
(integer) 0
HINCRBY
如果Hash里某个Field值的类型可以解析成数值，那么还可以用HINCRBY来做自增：
127.0.0.1:6379> hincrby user:1000 age 1
(integer) 1
127.0.0.1:6379> hincrby user:1000 age 1
(integer) 2
127.0.0.1:6379> hincrby user:1000 age 1
(integer) 3
127.0.0.1:6379> hincrby user:1000 age -1
(integer) 2
127.0.0.1:6379>
HINCRBYFLOAT
HINCRBYFLOAT key field increment
为哈希表 key 中的指定字段的浮点数值加上增量 increment 。
redis> HSET mykey field 10.50
(integer) 1
redis> HINCRBYFLOAT mykey field 0.1
"10.6"
redis> HINCRBYFLOAT mykey field -5
"5.6"
redis> HSET mykey field 5.0e3
(integer) 0
redis> HINCRBYFLOAT mykey field 2.0e2
"5200"
redis>
HKEYS
HKEYS key
获取所有哈希表中的字段
redis 127.0.0.1:6379> HSET myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HSET myhash field2 "bar"
(integer) 1
redis 127.0.0.1:6379> HKEYS myhash
1) "field1"
2) "field2"
HLEN
HLEN key
获取哈希表中字段的数量
redis 127.0.0.1:6379> HSET myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HSET myhash field2 "bar"
(integer) 1
redis 127.0.0.1:6379> HLEN myhash
(integer) 2
HSETNX
HSETNX key field value
只有在字段 field 不存在时，设置哈希表字段的值。
如果哈希表不存在，一个新的哈希表被创建并进行 HSET 操作。
如果字段已经存在于哈希表中，操作无效。
如果 key 不存在，一个新哈希表被创建并执行 HSETNX 命令。
redis 127.0.0.1:6379> HSETNX myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HSETNX myhash field1 "bar"
(integer) 0
redis 127.0.0.1:6379> HGET myhash field1
"foo"
redis 127.0.0.1:6379> HSETNX nosql key-value-store redis
(integer) 1
redis 127.0.0.1:6379> HSETNX nosql key-value-store redis # 操作无效， key-value-store 已存在
(integer) 0
HVALS
HVALS key
获取哈希表中所有值
redis 127.0.0.1:6379> HSET myhash field1 "foo"
(integer) 1
redis 127.0.0.1:6379> HSET myhash field2 "bar"
(integer) 1
redis 127.0.0.1:6379> HVALS myhash
1) "foo"
2) "bar"
# 空哈希表/不存在的key
redis 127.0.0.1:6379> EXISTS not_exists
(integer) 0
redis 127.0.0.1:6379> HVALS not_exists
(empty list or set)
用.NET Core操练HASH
准备工作
1.建一个Person类
class Person
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public DateTime JoinDate { get; set; }
public int Age { get; set; }
public decimal BankBlance { get; set; }
}
2.然后从网上抄袭了一个C#对象和Redis HashEntry[]之间转换的工具类：
static class RedisHelper
{
public static HashEntry[] ToHashEntries(this object obj)
{
PropertyInfo[] properties = obj.GetType().GetProperties();
return properties.Select(propertype =>
new HashEntry(propertype.Name, propertype.GetValue(obj).ToString()))
.ToArray();
}
public static T ConvertFromRedis<T>(this HashEntry[] hashEntries)
{
PropertyInfo[] properties = typeof(T).GetProperties();
var obj = Activator.CreateInstance(typeof(T));
foreach (var property in properties)
{
HashEntry entry = hashEntries.FirstOrDefault(g => g.Name.ToString().Equals(property.Name));
if(entry.Equals(new HashEntry())){ continue;}
property.SetValue(obj, Convert.ChangeType(entry.Value.ToString(), property.PropertyType));
}
return (T) obj;
}
}
命令测试
static void Hash()
{
using (ConnectionMultiplexer redis = ConnectionMultiplexer.Connect("localhost:6379"))
{
IDatabase db = redis.GetDatabase();
var person = new Person();
person.Id = 123;
person.FirstName = "Nick";
person.LastName = "Carter";
person.JoinDate = new DateTime(2019,4,20);
person.Age = 32;
person.BankBlance = 567.43m;
//1.HSET
db.HashSet("user:123", person.ToHashEntries());
//2.HGETALL 获取所有
HashEntry[] entries = db.HashGetAll("user:123");
foreach (HashEntry entry in entries)
{
Console.WriteLine(entry.Name);
}
Console.WriteLine();
//获取这个对象
Console.WriteLine("获取这个对象");
var thePerson = entries.ConvertFromRedis<Person>();
Console.WriteLine(thePerson.FirstName); //Nick
Console.WriteLine(thePerson.Age); //32
Console.WriteLine();
//3.HGET 获取一个
var age = db.HashGet("user:123", nameof(person.Age));
Console.WriteLine(age);//32
Console.WriteLine();
//4.HMGET 获取多个
RedisValue[] values = db.HashGet("user:123",
new RedisValue[]
{
nameof(person.Id), nameof(person.FirstName), nameof(person.Age), nameof(person.BankBlance),
});
foreach (RedisValue redisValue in values)
{
Console.WriteLine(redisValue);
}
// 123
// Nick
// 32
// 567.43
Console.WriteLine();
//5.HINCRBY 自增整数
var ageIncrement = db.HashIncrement("user:123", nameof(person.Age));
Console.WriteLine(ageIncrement); //33
ageIncrement = db.HashIncrement("user:123", nameof(person.Age),5);
Console.WriteLine(ageIncrement); //38
Console.WriteLine();
//6.HDEL 删除
var ageDelSuccess = db.HashDelete("user:123", nameof(person.Age));
Console.WriteLine(ageDelSuccess); //true
var ageDel = db.HashGet("user:123", nameof(person.Age));
Console.WriteLine(ageDel); //null
//7.HSCAN 迭代
IEnumerable<HashEntry> entriesEnumerable = db.HashScan("user:123");
foreach (HashEntry hashEntry in entriesEnumerable)
{
Console.WriteLine($"{hashEntry.Name}:{hashEntry.Value}");
}
// Id: 123
// FirstName: Nick
// LastName:Carter
// JoinDate:2019 / 4 / 20 0:00:00
// BankBlance: 567.43
}
}
HSCAN
HSCAN key cursor [MATCH pattern] [COUNT count]
迭代哈希表中的键值对。
http://www.redis.cn/commands/hscan.html
参考：
草根专栏，Redis in .NET Core 入门：(3) Hash
runoob，Redis 哈希(Hash)
